As compared with a liquid crystal display (LCD), an organic light emitting diode (OLED) display has many advantages such as self-illumination, response rapidity, wide view-angle, high brightness, vivid color, light weight and thin thickness, and thus it is deemed to represent the display technologies of the next generation.
In the prior art, for an organic electroluminescent device OLED, there are mainly two ways of fabricating an organic thin film therein:
A. a vacuum evaporation method, suitable for organic small molecules, characterized in that the formation of the organic thin film does not require a solvent and the thickness of the thin film is uniform, but it is not suitable for the production of large-sized products because of heavy device investment and low utilization rate of materials.
B. a solution process, comprising spin coating, inkjet printing, nozzle coating and so on, appropriate for polymeric materials and soluble small molecules, characterized by low device cost, so it is prominently advantageous in the production of large-scaled or large-sized products.
During the manufacture of a hole injection layer and a hole transport layer of an organic light emitting diode display panel, inkjet printing of the solution process is adopted in the prior art, because inkjet printing, as the most important technique of the solution process, has advantages such as low cost, unlimited dimension, and full color implementation. However, in a situation where an inkjet printing process is performed on a large-sized organic light emitting diode display panel, if inkjet printing is performed only once on a large-sized substrate, a great number of inkjet heads will be needed, which will make it difficult to calibrate jet volumes of all inkjet heads; if inkjet printing is performed multiple times by using a small number of inkjet heads, swath mura will occur at printing interfaces.
To sum up, in the prior art, when a hole injection layer or a hole transport layer of an organic light emitting diode display panel is manufactured by an inkjet printing process, a great number of inkjet heads will be required, or swath mura may be caused at printing interfaces.